5 Written questions
5 Matching questions
- What two things do we need to know to calculate work?
- What is a pulley?
- what is a machine?
- if you throw a ball, are you doing work? Explain.
- what is mechanical efficiency?
- a is a measure of how much of a machines energy is wasted, overcoming friction. No machine is 100% efficient, becuase there are always surfaces rubbing together.
- b a device that helps make work easier by changing the size or direction of a force.
- c you are only doing work on the ball as long as you are directly putting a force on it, in other words, when you are touching it.
- d we need to know the size of the force that was put on the object, and how far the object moved.
- e simple machine that is made of a wheel with a groove in it and a rope. it is usually used to life heavy objects.
5 Multiple choice questions
- a inclined plane that is wrapped in a spiral, usually on a rod, but not always.
- a simple machine that has a fulcrum, or pivot point.
- pushing a piece of heavy furniture up a ramp requires less input force, from you, than just lifting it up.
- turn a door knob (the wheel) the axle moves, to unfasten the door.
- the rate at which work is done.
5 True/False questions
What is the formula for power? → stays still, like the middle of a seesaw.
What is an inclined plane? → a simple machine with a straight, slanted surface.
does a machine reduce the amount of work that is being done? Explain. → Machines can change the size of the input force necessry. Also, they can change the direction of the force, which is especially helpfulo when we are trying to life somthing.
^ <--- Doing work? → Yes
---> ----> Doing work? → Yes